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Courtship in the male red‐sided garter snake is dependent on neural aromatase activity during winter dormancy
Author(s) -
Krohmer Randolph W.
Publication year - 2020
Publication title -
journal of experimental zoology part a: ecological and integrative physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.834
H-Index - 11
eISSN - 2471-5646
pISSN - 2471-5638
DOI - 10.1002/jez.2345
Subject(s) - courtship , biology , courtship display , endocrinology , mating , medicine , thamnophis sirtalis , dormancy , seasonal breeder , aromatase , zoology , botany , genetics , germination , cancer , breast cancer
The red‐sided garter snake exhibits a dissociated reproductive pattern, mating at a time when their gonads are quiescent and circulating sex steroids, initially reported to be low, have been found to be elevated during the breeding season. However, the only cue identified that initiates courtship behavior and mating in the red‐sided garter snake is an extended period of low‐temperature dormancy (LTD) followed by exposure to warm temperatures. In this study, we examined a possible association between winter dormancy, sex steroid hormone metabolism, and initiation of reproductive behavior in the male red‐sided garter snake. Upon emergence from winter dormancy, courtship behavior was assessed using attractive females as stimuli. Animals receiving implants containing 1,4,6‐androstatriene‐3,17‐dione (ATD), an aromatase inhibiter, showed little or no courtship behavior, while animals implanted with ATD + 17β estradiol (E 2 ) or blank implants exhibited normal courtship. In addition, neurons in the pathways critical in the control of reproductive behavior were examined using the Golgi method. Examination of brains collected upon emergence revealed animals implanted with ATD had a significantly reduced number of dendritic spines compared to controls and animals treated with ATD + E 2 . This study provides the first documentation that courtship behavior and mating in the male red‐sided garter snake appears to be controlled not by LTD alone, but in conjunction with sex steroid hormones. Moreover, behavioral data suggest that the aromatization of androgens during LTD appears to be critical for the initiation of reproductive behavior in the male red‐sided garter snakes.